Fingerprint authentication is attracting attention as one type of authentication system for identifying individuals. A fingerprint is unique in that it is different for every person, and that it does not change even with the lapse of time. Accordingly, it is said that fingerprint authentication is more reliable than the currently prevalent password authentication or the like. However, in recent years, damage resulting from forging a person's fingerprint and using such forged fingerprint (hereinafter referred to as the “forged fingerprint”) to pass the authentication and thereby conduct fraudulent acts is becoming a problem (for example, Patent Document 1).
[Patent Document 1] Japanese Translation of PCT Application No. 2007-511845
As a method of creating a forged fingerprint, known is a method of pressing a thin film of polyethylene resin or polyvinyl acetate resin on the surface of a person's finger so as to create a forged fingerprint. Upon fingerprint authentication, the surface that was pressed against the finger (that is, the surface on which the forged fingerprint was formed) is used as the front side, and this is attached to the surface of the finger of the person to be authenticated. With a finger to which such forged fingerprint is attached to the surface (that is, a fake finger), there is a problem in that, even if the spectral characteristics are measured upon fingerprint authentication, it is difficult to determine whether or not that finger is a fake finger since the spectral characteristics of the fake finger surface and the spectral characteristics of the finger surface of that person will basically be the same.